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Engine for Stewart Headwind?

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Kyle Boatright

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What's the appropriate engine for a Headwind? Personally, I'd be looking for something to spin a bigger prop slower. 40-50 hp at 2500 RPM should do it. Is there a recipe for that other than an A-65 (which is a little too much engine for the Headwind) or a Lycoming O-145 which also seems like a bit much. I'm not a big fan of direct drive VW's spinning 3000+ RPM in this application, and I have no idea if Stewart's "Maximizer" VW PSRU is a viable solution.

Obviously, the Verner radials would have been a good fit.
 

Hot Wings

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When the O-100 gets to market I think that would be a nice combination.

Maybe a Franklin twin?
 

TFF

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I would try being there on the list for a O-100. The big question about the maximizer is really if it’s available. I remember them made for RC in the late 70s.
 

Kyle Boatright

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I would try being there on the list for a O-100. The big question about the maximizer is really if it’s available. I remember them made for RC in the late 70s.
Seems like a CAD file and machine shop would make the Maximizer doable.
 

TFF

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I would think a O-145 would be a decent fit if it can handle the weight. It would look the vintage part. If you had all that for the Maximizer great. I thought it was unit only not plans.
 

BJC

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The original Headwind used a PSRU, designed, IIRC, by Stewart, on the VW engine. There were several VW PSRU’s back in the day. Might be possible to find or build one. I remember seeing multi-V belt VW reducers.


BJC
 

cluttonfred

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I believe that most Headwinds have flown with direct-drive VWs. Why complicate things? I suppose something like a big industrial V-twin with an Ace restive would be an option, but a straightforward VW conversion would be easier IMHO.
 

Kyle Boatright

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The original Headwind used a PSRU, designed, IIRC, by Stewart, on the VW engine. There were several VW PSRU’s back in the day. Might be possible to find or build one. I remember seeing multi-V belt VW reducers.


BJC
Stewart's PSRU was the Maximizer. Plans are still for sale at Stewart's new website:

 
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Topaz

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Stewart's PSRU was the Maximizer. Plans are still for sale at Stewart's new website:
IMHO, stay with what the plans specify, go direct-drive VW, or see if you can get your hands on an early-production O-100. If it were me, I'd probably go direct-drive VW if the Maximizer PSRU isn't cheap and easy to have made. As Matthew said, a lot of Headwind's have flown that way. Unless you're a particularly heavy guy, or live up near Denver or some other hot-and-high airport, I don't think you'll have climb-rate issues. If you feel that uncomfortable about a direct-drive VW, then the O-100 is heaven-sent for this application provided you can get one. I've seen one in-the-flesh, flying a real airplane. It's a sweet little motor that turns an impressive-sized prop with no PSRU.

Going too far afield is just asking to make the project more complicated and more trouble than necessary.
 

Pops

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Go with a direct drive VW. If you use a reduction drive its going to cost you a lot of added weight with the needed starter with a electrical system ,battery, etc.
VW don't have to spin 3000 rpm. My 1835 cc, VW engine in the high drag SSSC cruises at 80 mph at 2650/2700 rpm with a 60"x26" Culver prop burning 2.9/3.0 gph, with a 1200'+ ROC. Non-electric, 141 lb firewall forward weight.

The Headwind is NOT a low drag , fast , VW powed airplane that would need a small 54" dia prop turning at a high RPM .
 

Kyle Boatright

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Go with a direct drive VW. If you use a reduction drive its going to cost you a lot of added weight with the needed starter with a electrical system ,battery, etc.
I'd love to go direct drive. How draggy is the SSC compared to the Headwind (which wasn't named that by accident).

As to the Maximizer, Stewart says you can still hand-prop an aircraft equipped with one.
 

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I have known about the Headwind B back when RCM published a plan for a RC model. I like to compare different planes piece by piece. The Baby Ace and the Legal Eagle are both comparable to the Headwind. They are all comparable in size. The LEXL has more wing area and only slightly shorter fuselage.

It would be interesting to see component weights to see where they differ. Engine weight is probably the biggest percentage, wheels and brakes are going to add up different, but spar and fuselage tubing have to be close.
 

Turd Ferguson

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The Headwind (N73JR) now owned by Armando Escalante with a Maximizer. He flies the crap out of that plane. Nothing like hanging your arm out the window with short sleeves. headwind.jpg
 

fly2kads

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I ordered plans for both the Headwind and the Maximizer reduction from Mr. Stewart a couple of years ago. As I have stated here before, the Headwind plans are fantastic. At that time, Mr. Stewart was having technical issues with his plotter, and couldn't provide a complete set of drawings for the Maximizer. He sent me what he could, and refunded my purchase for the Maximizer, without my having to ask. He was very gentlemanly and apologetic for not being able to deliver on my order. From the partial drawings, it looks like the Maximizer could be built by someone experienced with a lathe, drill press, and a band saw; I don't know if any other machine tools would be required.

That said, there are a number of Headwinds happily flying with direct drive VWs. There are options for building a large-displacement, low-rpm VW conversion that just weren't available at the time the Headwind was designed. I also agree that Pete's O-100 would be a very attractive option.

Edit: In fact, the current Headwind prints just show a direct-drive VW installation.
 
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Pops

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Here's the Maximizer from Don's plans: I wouldn't fly without it but I'd just make my own because the original cast pieces are not readily available. View attachment 103403
That is a 1200 cc, 40 HP , VW engine. Can tell by the straight down intake tube on top of the head. Also a 40 HP carb. They do make a oversize set of pistons and cylinders for 1300 cc and 5 more HP. 77cc to 83 mm's.
The first 35 hrs I flew on the SSSC was with a 1200 cc, VW engine. Not as much difference as you would think between a 1200 cc and a 1600 cc VW engine because the 1200 cc engine devolopes its max torque at a lower rpm. So at the straight drive prop rpm the 1600 cc engine is not producing very much more HP than the 1200 cc engine.
 
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